The eukaryotic cell cycle is central to proliferation, development, and many health issues including cancer. The budding yeast is a well-established model system for studying evolutionarily conserved aspects of cell cycle control. The present application seeks to use recently developed proteomic tools to identify and examine the roles of cyclin-associated proteins in cell cycle control. Additional related experiments on the fundamental nature of the cyclin-dependent kinase/APC proteolysis oscillator are proposed. This oscillator is highly conserved and essential for cell cycle control throughout the eukaryotes.